Patience equals flavour: the importance of the ‘jangs’ and fermentation in Korean cuisine

by Great British Chefs 23 November 2021

Korean dishes are known for their big, bold, seasonal flavours – but the foundations of the cuisine almost always begin with something fermented. Learn more about the importance of ferments in Korean cuisine, from kimchi to the ‘jangs’ used throughout the country’s cooking.

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Every national cuisine in existence has its own distinct features, flavours, textures and techniques. It’s what gives a country its unique culinary – and in many cases cultural – identity. Korea may share some culinary characteristics with its neighbours, but if you look a little closer it becomes clear that it is home to one of the most distinctive cuisines in all of Asia.  In particular, traditional Korean food (known as hansik) simply wouldn’t be the same without an array of unique fermented products that add buckets of depth and complexity to dishes. 

History points to the existence of fermented foods in Korea as far back as 1500 BC; evidence of fermented beans have been found in digs of historical Bronze Age sites in the Korean peninsula, suggesting that people were using fermentation in cooking up to 4,000 years ago. Nowadays, ferments are one of the cornerstones of Korean cookery, with many of the country’s most iconic dishes flavoured with fermented sauces and pastes. This collection of ingredients is often referred to as the ‘jangs’ (as the names for them often end in -jang, which roughly translates to ‘sauce’ or ‘paste’) and are regarded as essential ingredients in any Korean kitchen. Although there are loads of different jangs including eojang (made from fermented and brined fish) and cheonggukjang (a fast-fermented bean paste), the three most important are ganjang, doenjang, and gochujang; all of which are made from a block of fermented soybeans called meju.

Traditionally made towards the end of autumn, meju is produced by soaking and then boiling soybeans for between five and six hours. The cooked beans are then dried, crushed and then after a week moulded into large bricks. These soybean blocks are tied and covered in rice straw (the vegetative part of the rice plant), which encourages the growth of mould, before being left to hang and ferment for two to three months. When they’re ready, the bricks are eventually removed from the straw, washed and brined in a saltwater solution, then finally left to ferment for a further month in Korean earthenware pots called onggi. During this time, the concoction separates, producing two of the essential ‘jangs’ – soy sauce (ganjang) and fermented bean paste (doenjang). These two products are then separated and can then be left to age further.


There are multiple different types of ganjang used in Korean cookery, all of which differ slightly in flavour, colour and the way they’re used. The direct by-product of doenjang is known as guk-ganjang and is the most traditional of the Korean soy sauces, having been used for thousands of years. Its light colour and rich salty flavour means that it’s most commonly used in moderation to season soups and stews (guk actually translates as ‘soup’ in Korean). Yangjo-ganjang is a more modern soy sauce which was adopted from Japan production methods in the nineteenth century. This darker and sweeter sauce tends to be used for braises and marinades and is either made by naturally fermenting soybeans with wheat or rice for six-months, producing a more premium product. You can also find jin-ganjang, which is a blended, cheaper, less intense soy sauce that's better suited to dishes cooked over a fierce heat (such as Korean barbecue).

Meju is made by hanging blocks of soybean with rice straw and leaving them to ferment.
Doenjang-jjigae is a traditional Korean stew made from doenjang (fermented soybean paste).


Doenjang is the brown paste leftover from the ganjang production process and in its purest form is made up of just fermented soybeans and brine. The paste’s rich savouriness is balanced with a slight bitterness and it’s used to give a savoury punch to dishes including the popular Korean stew doenjang-jjigae. It’s also combined with gochujang to make a dipping sauce called ssamjang, often served alongside barbecued meat. Doenjang has additionally been used to treat high blood pressure over the years and is known to have lots of other health benefits too. Just a spoonful of this thick paste added to a dish will imbue it with a deep, rich complexity in a similar way to Japan’s miso – but doenjang offers a fuller, more savoury flavour that makes it unique. 


In contrast, gochujang is made using a small amount of meju which has been dried and ground up, in combination with glutinous rice and gochugaru (Korean chilli flakes). This addition of chilli means gochujang has a fiery heat that builds throughout eating a dish, but still has that savoury presence with a slight sweetness from the rice. Gochujang is one of the most fundamental and common ingredients in Korean cookery and is also incredibly versatile. This means that you’ll see it being used in everything from salad dressings to dipping sauces and marinades in traditional dishes like bulgogi. It can even be mixed with other ingredients like sesame oil and vinegar to create other jangs.


The jangs may be at the core of Korean cuisine, but it wouldn’t be right to discuss fermentation in Korea without at least briefly mentioning kimchi. Probably Korea’s most famous export, kimchi is both an ingredient and a dish in itself, made from a mixture of vegetables which have been left to ferment in a highly flavourful paste. It’s ubiquitous at the Korean dinner table, often served daily alongside every meal.

Families across Korea will all add slightly different vegetables and spices to their kimchi and recipes are often passed down through generations. This means that different kimchis vary dramatically; they can be made with cabbage (the most common variety), radishes, include fish and in some cases even meat. In terms of how kimchi is used in Korean cookery, it’s most commonly served as a side dish to accompany various meals and also sometimes as an appetiser. However, its complex flavour means it’s also used as an ingredient to cook with, where its flavour will mellow once heated. You’ll find everything from kimchi-fried rice and stews to kimchi pancakes and even kimchi-topped pizza.

It may be one of the oldest and most natural processes of enhancing flavour but Korea’s culinary identity today continues to be rooted in fermentation. The complex flavours associated with the cuisine would not be present without it; neither would kimchi – the country’s most famous dish. Ferments may be present in cuisines across the world, but few have a gastronomic history more intertwined with the process than Korea.